Mobile use of various personal computers, e.g. PDA (Personal Digital Assistant) and intelligent telephones, has become increasingly popular. Using such terminal equipment the user is in connection with the host, both in the office and outside the office. Some modern user interfaces for terminal equipment, such as Windows 95, allow connection and disconnection of so-called plug-and-play accesses even while the application is running.
It is known in the state of the art to choose the routing at nodal points of a network. FIG. 1 in the appended drawing shows how a piece of terminal equipment is connected through an intermediary network (internet) to a host in a known manner. E.g. when moving outside the office in situation 1, terminal equipment TE connects with the AP1 (Access Point). In the messages which it sends, the terminal equipment uses as source address the address reserved by the access point for the terminal equipment. A node wishing to be in connection with the terminal equipment will for its part use said address as destination address for messages which it sends. When the access point is changed, this address will be exchanged, e.g. in the situation 2 shown in FIG. 1 for the address reserved by access point AP2. By using e.g. the Mobile IP protocol, the access point used currently by the user may be registered in the HA (home agent), which allows use of the same address irrespective of the access point. However, the user must choose manually the access point to be used at each time. It is not possible in this arrangement to exchange the access point automatically for another access point while terminal equipment TE is moving, e.g. to replace AP1 with AP2, but the terminal equipment must itself actively connect and register with anew access point in order to bring about the connection. The user can be connected with one access point at a time.
The connection from terminal equipment TE is set up using the available access. Various network accesses are e.g. the Ethernet or IR (infra-red) at the office or the GSM (Global System for Mobile Communications) data access, especially the GPRS (General Packet Radio Service) access, outside the office. One generally used way of access is by connecting a PCMCIA access card to terminal equipment TE. The user may remove and connect these accesses as he desires, whereby the connection is set up by way of the access which is connected at each time. Several cards may also be connected at the same time to terminal equipment TE, but hereby only one of them is used, e.g. the access which was connected first to the terminal equipment, and the access is not exchanged automatically for another while the connection is in use, even if the connection through the used access is lost.
It is a problem with state-of-the-art accesses that the connection of the terminal equipment with the data network is not flexible. The user must himself actively carry out the choice of the access to be used as well as its connection and registration with the network nodal point. In addition, when exchanging the access it is sometimes necessary to close the application and to restart the system in order to begin using a new access.